This application claims the priority of German application 198 53 189.3, filed in Germany on Nov. 18, 1998, the disclosure of which is expressly incorporated by reference herein.
The invention relates to a hot-chamber diecasting machine for processing magnesium melts, comprising a casting vessel with an ascending bore, a conical mouthpiece, a nozzle attached to the mouthpiece, and an inductively operating heating device which is operated at a medium frequency or at a frequency at the lower limit at the high frequency, a ring inductor being placed in the plane of the covering of the crucible for the melt around the casting vessel.
A hot-chamber diecasting machine of this type is known from German Patent Document DE 195 43 805A1 (incorporated in part in U.S. Pat. No. 5,960,854). In order to achieve a heating in the area of the neck of the casting vessel, a ring inductor is provided there which is constructed of two halves but which then, because the neck of the casting vessel is very difficult to access, at least in the installed condition of the casting vessel, must be mounted and possibly demounted at high expenditures. As a rule, it becomes necessary in this case to also detach the casting vessel in order to have better access to its neck.
From German Patent Document DE 195 31 161A1 (incorporate in part U.S. Pat. No. 5,960,854), it is known to assign inductors to the mouthpiece area of the casting vessel and to the nozzle, which inductors are constructed as tubes insulated on the outside and are pushed as sleeve-shaped spirals in each case axially onto the mouthpiece area and the nozzle. These tubes are acted upon by a medium frequency or by a frequency at the lower limit of the high frequency, and air flows through these tubes in order to avoid an overheating. When used for hot-chamber diecasting machines by means of which magnesium melts are to be processed, such a further development has the advantage that there can be no contact of water, which is normally used for the cooling, with magnesium.
It is an object of the present invention to find a solution for easily mounting the ring inductor in the area of the neck of the casting vessel, which neck area can also be further developed such that the ring inductor can also be cooled with air.
For achieving this object, it is provided in the case of a hot-chamber diecasting machine of the initially mentioned type that the ring inductor includes at least one bendable tube made of an elastic material which forms a one-piece ring which is open at one point and is provided there with connections for energy and for cooling air flowing through.
If the elasticity of the tube ring is so large that the tube ring can be bent open at its open point by the extent of the diameter of the casting vessel in the area of the crucible covering and can be slid laterally onto the neck of the casting vessel, this further development has the considerable advantage that a relatively easy mounting can be carried out without the necessity of detaching the casting vessel from its fastening on the crucible.
As a further development of preferred embodiments of the invention, the tube may be a flat tube which is bent about an axis extending in parallel to its larger lateral surfaces. In this case, in a further development of the invention, one of the larger lateral surfaces of the flat tube can be connected with a carrier band, in which case the carrier band and the flat tube may be surrounded by an insulating woven fabric for the thermal and electric insulation.
As a further development of the invention, the insulating woven fabric can consist of a band which is wound around the flat tube and the carrier band.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.